1. Field of the Invention
The present invention relates to telecommunications and, more particularly, to a method and system for notifying a multi-mode mobile station of an incoming call.
2. Description of Related Art
There is an increased interest in using more diverse types of wireless access technologies for mobile devices. Different wireless access technologies may be used to provide wireless coverage in different geographic areas. In addition, different wireless access technologies may be used to provide different capabilities for transmitting and receiving voice, data, and/or other media. For example, wireless wide area networks (WWANs), which often use wireless access technologies such as CDMA, TDMA, or GSM, typically provide wireless coverage in relatively large geographic areas. However, in many cases, WWANs do not provide good wireless coverage in buildings. In addition, many WWANs have a relatively limited bandwidth for transmitting and receiving media. However, wireless local area networks (WLANs), which may use wireless access technologies, such as IEEE 802.11, Bluetooth, HiperLAN, and Multichannel Multipoint Distribution Service (MMDS), have been used to provide wireless coverage in more limited areas, such as the inside of buildings. In addition, WLANs can often transmit and receive media at a higher rate than many WWANs.
With this increased interest in using diverse wireless access technologies to provide wireless coverage has come an increased interest in providing multi-mode mobile stations that can communicate using more than one type of wireless access technology. For example, a multi-mode mobile station may have one interface for communication with a WWAN, using a wireless access technology such as CDMA, and another interface for communication with a WLAN, using a wireless access technology such as IEEE 802.11. Thus, a multi-mode mobile station could use a WLAN for wireless communication when the multi-mode mobile station is operating in certain locations, e.g., indoor locations, but may use a WWAN for wireless communication when the multi-mode mobile station is operating in other locations, e.g., outdoor locations. The fact that a multi-mode mobile station could be accessible via different networks at different times can cause challenges. In particular, when a call is placed to a directory number associated with a multi-mode mobile station, the question becomes how best to try to reach the multi-mode mobile station and notify it of the incoming call. For example, in existing systems, if the incoming call is sent to the WWAN but the multi-mode mobile station does not answer the call, the call may be sent to voicemail—even though the multi-mode mobile station may have failed to answer because it was in communication with the WLAN, rather than the WWAN.
Accordingly, there is a need to provide improved methods and systems for notifying multi-mode mobile stations of incoming calls.